APA (7th ed.) Citation

Wrobel, S. (1987). Higher order concepts in a tractable knowledge representation.

Chicago Style (17th ed.) Citation

Wrobel, Stefan. Higher Order Concepts in a Tractable Knowledge Representation. Berlin, 1987.

MLA (9th ed.) Citation

Wrobel, Stefan. Higher Order Concepts in a Tractable Knowledge Representation. 1987.

Warning: These citations may not always be 100% accurate.